billseph Posted March 3, 2012 Share Posted March 3, 2012 I've got a simple question about a hose routing thought I'm having. For background info purposes I am diagnosing vacuum leaks and doing some general tidying up of the engine bay while planning the routing of a future intercooler setup in my L28ET swapped 240Z. So my question is in regards to routing of the PCV and valve cover vent. I'd like to put a "tee" fitting in line with the PCV hose (between the crankcase and 1-way PCV valve on the intake manifold). I'd like to run the valve cover vent hose to this tee (instead of pre-turbo to the AFM boot as it is run stock) Does anyone see this as problematic?? It seems like "no big deal" to me, but I wanna make sure I'm not doing something wrong (obviously the Nissan engineers ran lines the way they did for some reason). My PCV valve seems to be operating perfectly as a check valve...blow through one end and it's open...blow through the other end and it's closed, so I won't be pressurizing anything I shouldn't be when boosting. Quote Link to comment Share on other sites More sharing options...
78zstyle Posted March 3, 2012 Share Posted March 3, 2012 Do you then plan to run it to a catch can with a vent? It has to get out somehow.. unless you mean in the T have the open end just vent to atmosphere? Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted March 3, 2012 Share Posted March 3, 2012 It is best to run it pre-turbo, like stock. Teeing into the brake booster hose, will require a check valve in line, so that the crank case is not pressurized, but essentially, you'd be making the same connection as the crankcase vent below the intake to the intake itself. The reason it is best to route is as OEM, is because under boost, the crank case vent will close, to keep from pressurizing the crank case, but with the cam cover connected pre-turbo, there will be a little bit of vacuum created here to help create a crankcase vacuum during WOT/boost, helping to seal rings and pull crankcase vapours from the crankcase. Quote Link to comment Share on other sites More sharing options...
billseph Posted March 3, 2012 Author Share Posted March 3, 2012 It is best to run it pre-turbo, like stock. Teeing into the brake booster hose, will require a check valve in line, so that the crank case is not pressurized, but essentially, you'd be making the same connection as the crankcase vent below the intake to the intake itself. The reason it is best to route is as OEM, is because under boost, the crank case vent will close, to keep from pressurizing the crank case, but with the cam cover connected pre-turbo, there will be a little bit of vacuum created here to help create a crankcase vacuum during WOT/boost, helping to seal rings and pull crankcase vapours from the crankcase. Thanks...this is the info I was looking for, and losing the vacuum effect (that the stock routing of the valve cover vent provides...even under boost) is what I was concerned about...just needed an explanation of the benefits/drawbacks of. I mean...with the setup I had in mind the engine would essentially be entirely sealed (no PCV or valve cover vent) unless you were not in boost...so I will definitely run the valve cover vent to a pipe pre-turbo (same as stock) once I setup the intercooler piping. Also just out of curiousity, does anyone know at what pressure the PCV valve acts as a check valve...is it just ANY positive pressure that shuts it?? And thank you guys for the replies Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted March 5, 2012 Share Posted March 5, 2012 Theres no spring in them if theres no vacuum or theres pressure its shut Quote Link to comment Share on other sites More sharing options...
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